Preparation of vegetable oil-based monomers for use in thermosetting resins

ABSTRACT

The present embodiments herein generally relate to thermoset resins that are derived from vegetable oil based sources, including fibrous plant sources. The utilization of plant based oil as starting materials makes the technology a green alternative to currently available solutions. This, coupled with the novel synthetic methods that are utilized, results in a transformation of the plant based oils into useful, durable, and resilient thermoset resins.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. 119 to U.S. applicationSer. No. 62/384,819, entitled “PREPARATION OF VEGETABLE OIL-BASEDMONOMERS FOR USE IN THERMOSETTING RESINS”, filed on Sep. 8, 2016, andincorporated herein by reference in its entirety.

BACKGROUND

Vegetable oils (VO) and derivatives have been important industrialfeedstock chemicals and intermediates. In recent years, there has been agrowing interest in development of VO-based alternative thermosettingpolymers, such as polyurethanes, unsaturated polyesters, and epoxies.Reactions on the double bonds and ester bonds of the unsaturated fattychains of VOs may introduce various polymerizable functional groups and,hence, turn VO molecules into bio-based monomers for polymers with lesscarbon footprint. When the VO-derived monomers are used as co-monomers,the long fatty acid chains of VO provide certain flexibility and/ortoughness for some brittle resin systems. However, when utilized aloneas base resin monomers, VO-derived monomers tend to give the crosslinkedpolymer network insufficient modulus and strength. This is mainly due tothe VO-based monomers being built on the triglyceride structure in whichthe polymerizable groups are generally linked by a long flexible fattychain. This results in polymer materials with poor mechanicalproperties, which are not appropriate for applications such as compositematrix polymer and protective coatings. There are different ways toimprove strength and modulus, including use of rigid co-monomers, curingwith rigid hardeners, or increase the crosslink density by introducingmore polymerizable groups.

BRIEF SUMMARY

The present embodiments herein generally relate to thermoset resins thatare derived from vegetable oil. The vegetable oil may be obtained fromfibrous plant sources, such as the hempseed plant. The utilization ofplant-based oils as starting materials makes this technology a greenalternative to currently available solutions. This, coupled with thenovel synthetic methods that are utilized, allow the plant-based oils tobe transformed into useful and durable thermoset resins. Thus, theplant-based oils are uniquely transformed to durable and resilientthermoset resins.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

To easily identify the discussion of any particular element or act, themost significant digit or digits in a reference number refer to thefigure number in which that element is first introduced.

FIG. 1 illustrates an embodiment of a monomer production process 100.

FIG. 2 illustrates an embodiment of a monomer production process 200.

FIG. 3 illustrates an embodiment of a monomer production process 300.

FIG. 4 illustrates an embodiment of a monomer production process 400.

FIG. 5 illustrates an embodiment of a monomer production process 500.

FIG. 6 illustrates an embodiment of a monomer production process 600.

FIG. 7 illustrates an embodiment of a monomer production process 700.

FIG. 8 illustrates an embodiment of a monomer production process 800.

FIG. 9 illustrates an embodiment of a monomer production process 900.

DETAILED DESCRIPTION

Disclosed herein are biobased monomer compounds derived from fatty acids(FAs) that are the hydrolysis products of VOs. VO-based polymermaterials are mostly based on the monomers obtained by derivatization ofthe carbon-carbon double bonds in the chains of the unsaturated fattyacids of the oil (Scheme 1a). Therefore, when the monomer is built onthe triglyceride structure of the oil, the properties of the resultingthermoset is determined by the distance between the two polymerizablegroups from one fatty acid to another fatty acid on the same oilstructure. This distance is the same as that from a double bond of oneunsaturated fatty acid to the double bond of another unsaturated fattyacid and is at least 21 single chemical bonds, making the curedthermosets soft. When the monomer is directly built on the structure ofan unsaturated FA derived from hydrolysis of oil, one polymerizablegroup is introduced through the carboxyl end group of the FA, inaddition to the ones derived from the double bonds, as shown in Scheme1b. In this way, the distance between two polymerizable groups isreduced (it is 16 in Scheme 1 b). As a result, thermosetting polymersbased on the FA-derived monomers tend to give higher crosslink density,resulting in improved strength and modulus. The FAs that may be utilizedmay be obtained from a variety of resources, including hempseed oil,cottonseed oil, soybean oil, castor oil, tung oil, and linseed oil.Three types of FA-derived monomers are presented by way of example:acrylate monomers, thiol-containing monomers, and silane-containingmonomers. These monomers may be polymerized or co-polymerized via eitherthermal initiation or photo initiation to form crosslinked networkstructures.

Hydrolysis of Hempseed Oil

In one embodiment, a sodium hydroxide (16 g) solution in 140 mLethanol-H₂O (1:1, V/V) is charged into a 1-L three-necked round-bottomflask equipped with reflux condenser, magnetic stirrer, and thermometer.After the solution is heated to 70° C., hempseed oil (100 g) is dropwiseadded to the reaction system using a dropping funnel. The reaction iscontinued at 70° C. for 2 hours. After that, the reaction mixture isadjusted to pH 2-3 using 1 M hydrochloric acid, and then the reaction iscontinued at 70° C. for another hour. After the reaction is cooled down,the mixture is extracted with ethyl ether and is washed with de-ionized(DI) water three times. The ethyl ether solution is dried over magnesiumsulfate. Finally, the ethyl ether is removed by vacuum distillation,resulting in a viscous mixture of hydrolyzed hempseed oil fatty acids(HFA, yield 90%). The composition of fatty acids in hydrolyzed hempseedoil is determined by Gas Chromatography-Flame Ionization Detector(GC-FID) using a standard fatty acid methyl esters (FAME) procedure.

Acrylation of Hydrolyzed Hempseed Oil Fatty Acid (HFA)

The HFA is directly acrylated in the presence of BF₃.Et₂O, as shown inScheme 2. Representative reaction conditions are as follows: the mixtureof HFA, acrylic acid (AA) and BF₃.Et₂O in the molar ratios of1:27.4:1.37 are reacted under stirring at 80° C. for 4 hours. Dependingon the size of reaction, two different work-up procedures may beemployed. For the small size reactions, the excess AA and catalyst areremoved by NaHCO₃ aq. washing directly. For the large size reactions,the excess AA and catalyst are recovered by distillation at 35-45° C.under reduced pressure, and the recovered AA and catalyst are reused.The yellow liquid acrylate hempseed oil fatty acid (AHFA) is obtained(yield 90%).

Methacrylation of AHFA

A 100-mL round-bottom flask equipped with a magnetic stirrer is chargedwith 0.10 mol AHFA, 0.002 mol (2 mol % on fatty acid) of benzyltrimethyl ammonium bromide (BTMAB), and 1 wt % hydroquinone. The mixtureis allowed to warm under argon atmosphere for about 15 minutes in an oilbath preheated to 120° C. Glycidyl methacrylate (GMA, 0.11 mol) issubsequently added dropwise using a dropping funnel. The reactionprogress is monitored over 6 hours by thin layer chromatograph (TLC)using methylene chloride and ethyl acetate (7:3). Due to the competingside reactions, further addition of up to 0.1 molar equivalent of GMAand additional reaction time may be utilized to react all of the AHFA.Two major oxirane ring-opening products are observed as the reactionproceeded to completion within a total of 8-10 hours. To produce apurified sample for characterizations, the dark-colored reaction mixtureis allowed to cool to room temperature and then passed through a shortsilica (200 mesh) column using 20% ethyl acetate in methylene chlorideto remove the catalyst and dark brown particulates. A yellowish brownliquid AHFA-GMA (mixture of 1a & 1b, yield 75-86%) is obtained.

Synthesis of castor oil fatty acid methacrylates (2a & 2b)

In another embodiment, the synthesis of the compound depicted in Scheme3 is achieved in a two-step process. A 100-mL round-bottom flaskequipped with a magnetic stirrer is charged with 29.85 g (0.10 mol)ricinoleic acid (RA, from castor oil), 0.46 g (0.002 mol, 2 mol % on thebasis of fatty acid) BTMAB, and 0.3 g (1 wt %) of hydroquinone. Themixture is allowed to warm under argon atmosphere for about 15 minutesin an oil bath preheated to 120° C. Glycidyl methacrylate (GMA, 15.63 g(1.1 equivalent)) is subsequently added dropwise using a droppingfunnel. The reaction progress is monitored over 6 hours by TLC. Due tothe competing side reactions, further addition of up to 0.1 equivalentof GMA and additional reaction time may be utilized to ensure all of theRA reacted. Two major oxirane ring-opening products are produced as thereaction proceeded to completion within a total of 8-10 hours. Toprepare the purified sample for characterizations, the dark-coloredreaction mixture is allowed to cool to room temperature and passedthrough a short silica (200 mesh) column using 20% ethyl acetate inmethylene chloride to remove the catalyst and dark brown particulates. Ayellowish brown liquid (RA-GMA) is obtained (yield 75-87%).

Before the dropwise addition (46.25 g, 0.3 mol; 3 equivalent to RA) ofmethacrylic anhydride (MAA) to the product mixture from above, acatalytic amount (0.12 g, 1 mol %) of 4-(dimethylamino)pyridine (DMAP),30.35 g triethylamine (TEA) (3 molar excess), and 1 wt % hydroquinoneare added. The reaction is allowed to proceed optimally at 70° C. andmonitored by TLC for 4-6 hours under argon atmosphere. TLC determinedthe presence of one major product in addition to some minor impuritiesthat account for unreacted excess methacrylic anhydride, residual tracesof GMA and dimethacrylates. The reddish brown reaction mixture isdissolved in ˜300 mL of methylene chloride and washed with 500 mL (6×˜80mL) each of distilled H₂O, 10% (v/v) dilute hydrochloric acid, saturatedsodium bicarbonate (NaHCO₃) solution and saturated brine. The organicphase is dried over anhydrous magnesium sulfate (MgSO₄) and concentratedunder reduced pressure at no more than 60° C., yielding ˜40 gyellowish-dark brown liquid product MARA-GMA (mixture of 2a & 2b). Toprevent premature gelation, the product is stored in a closed container,away from direct sunlight, UV, and heat sources.

Another embodiment is depicted in Scheme 4, which illustrates thesynthesis of the acrylate compounds 3 & 4 in a three-step process. After28 g HFA and 21.2 g sodium carbonate are mixed well in 20 mL methylenechloride (CH₂Cl₂), 73.6 g meta-chloroperoxybenzoic acid (m-CPBA, 75 wt%) dissolved in CH₂Cl₂ at 0.1 g/ml concentration is added dropwise at areaction temperature below 15° C., and then the reaction is reacted for4 hours to complete the epoxidation. The reaction mixture is washed with10 wt % sodium sulfite and then by 10 wt % aqueous sodium bicarbonate.CH₂Cl₂ is removed by in vacuum rotary evaporation and 30 g productepoxidized hempseed oil fatty acid (EHFA, 96% yield) is obtained.

31.2 g EHFA, 0.46 g, BTMAB, and 0.3 g (1 wt %) of hydroquinone is mixedwell in flask. After the mixture is protected under argon atmosphere andplaced in an oil bath of 120° C. for about 15 minutes, glycidylmethacrylate (GMA, 15.63 g (1.1 equivalent)) is added dropwise. Thereaction progress is monitored over 6 hours by TLC. Next, the reactionmixture is purified by silica gel column to remove the impurity by ethylacetate and methylene chloride, then product EHFA-GMA is obtained withthe yield 87%.

45.4 g EHFA-GMA, 1.15 g BTMAB, and 0.9 g (2 wt %) of hydroquinone ismixed and allowed to warm under argon atmosphere for about 15 minutes inan oil bath preheated to 100° C. The mixture of acrylic acid/acrylicanhydride (R═H) or methyl acrylic acid/methacrylic anhydride (R═CH₃)(acid/anhydride=0.15 mol/0.3 mol) is added dropwise into the reactionmixture. The reaction progress is monitored over 6 hours by TLC.Subsequently, the reaction mixture is purified by silica gel column toremove the impurity by ethyl acetate and methylene chloride, thenproducts 3 and 4 are obtained with the yield 65% and 72%, respectively.

Silane Modified (Dual Curing, Moisture Curable)

Another embodiment is depicted in Scheme 5, which depictssilane-modified acrylated or methacrylated FA through residualhydroxyls. As depicted, the result in Scheme 2 (referred to as (1)),RA-GMA (an intermediary in Scheme 3, prior to reacting with MAA), and 3& 4 (EHFA-AA/MA-GMA, a derivative from the intermediary in Scheme 4) isreacted with an acrylate silane group to form AHFA-GMA-A-Silane (Scheme5-I), RA-GMA-A-Silane (Scheme 5-II), or EHFA-AA/MA-GMA-A-Silane (Scheme5-III), respectively. A methacrylate functional group may also beutilized to produce AHFA-GMA-MA-Silane, RA-GMA-MA-Silane, orEHFA-AA/MA-GMA-MA-Silane when using methacrylate silane as the silaneagent.

The fatty acid derivatives with multi-acrylic silane groups are preparedby the following general procedure. The reactions are carried out in aflask equipped with a stirrer, dropping funnel, thermometer, and refluxcondenser capped with a drying tube. Silane agent is mixed withAHFA-GMA, RA-GMA, or EHFA-AA/MA-GMA at a molar ratio of 1:1 to 1:4(based on the hydroxyl groups containing in the reagents), and themixture is stirred for 2-3 h at 90-100° C. Liberated methanol isdistilled off under reduced pressure (on a rotary evaporator), givingthe products with the yield of 67-75%.

Another embodiment is depicted in Scheme 6, which depictssilane-modified (meth)acrylate FA through residual hydroxyls. Thisprocess is similar to Scheme 5; however, vinyl functional silanereplaces acrylate/methacrylate-silane to produce AHFA-GMA-V-Silane,RA-GMA-V-Silane, and EHFA-AA/MA-H-V-Silane.

The fatty acid derivatives with multi-vinyl silane groups are preparedby the following general procedure. The reactions are carried out in aflask equipped with a stirrer, dropping funnel, thermometer, and refluxcondenser capped with a drying tube. Silane agent is mixed withAHFA-GMA, RA-GMA or EFA-AA/MA-GMA-H at a molar ratio of 1:1 to 1:4(based on the hydroxyl groups containing in the reagents), and themixture is stirred for 2-3 h at 90-100° C. Liberated methanol isdistilled off under reduced pressure (on a rotary evaporator), givingthe products with the yield of 77-85%.

Epoxy Type

Yet another embodiment is depicted in Scheme 7, which depicts fattyacid-derived epoxy (dimer acid-derived, and fatty acid-derived diacidand triacid). In one embodiment, the dimer acid (DA) is reacted withepichlorohydrin (ECH) to form DA-diepoxy (as shown in Scheme 7-I). Inanother embodiment, the FA is first reacted with either acrylic acid orfumaric acid to produce fatty acid-derived diacid (FA-diacid) and fattyacid-derived triacid (FA-triacid), which are then reacted with ECH toproduce a FA-diepoxy or FA-triepoxy (as shown in Scheme 7-II & 7-III).

The preparation of DA-diepoxy follows a general procedure stated here.To a 50 mL flask equipped with reflux condenser, magnetic stirrer, andthermometer are charged 3.74 g DA, 18.5 g epichlorohydrin, and 0.023 gbenzyltriethyl ammonium chloride. The reaction temperature is raised to117° C. and the reaction continued at that temperature for 2 h. Afterthe mixture is cooled to 60° C., 0.8 g sodium hydroxide and 1.12 gcalcium oxide is charged. The mixture is stirred at 60° C. for 3 h andthen filtered by diatomaceous earth (e.g., Celite®) and filter paper.The solid is discarded. After the excess epichlorohydrin is distilledunder vacuum at 100° C. from the filtrate, a light yellowish liquidproduct is obtained with a yield of 85%-90%. Since the dimer fatty acidis a mixture of various isomers with similar structures, DA-diepoxy isnot further purified and utilized as prepared.

The preparations of FA-triacid follow a general procedure stated here.129 g crude adduct of fumaric acid and conjugated FA is dissolved in 500mL acetone and neutralized by 50% NaOH solution drop by drop until thepH value reaches 7. After the acetone is removed, the precipitatedtricarboxylic acid is extracted with ethyl acetate. The organic layer isneutralized using HCl and dried by NaSO₄ for 12 h and then the ethylacetate is removed using a vacuum rotary evaporator to obtain a whitesolid FA-triacid (yield: 99%).

3.5 g FA-triacid, 18.5 g epichlorohydrin, and 0.061 g benzyltriethylammonium chloride are added to a 50-mL flask. The reaction temperatureis raised to 117° C. and the reaction continued for 2 h. After themixture is cooled to 60° C., 1.2 g sodium hydroxide and 1.68 g calciumoxide are charged. The mixture is stirred at 60° C. for 3 h and thenfiltered with powder Celite. After the excess epichlorohydrin isdistilled under vacuum at 100° C. from the filtrate, a yellowish viscousproduct (4.56 g) is obtained. The product is purified using a silica gelcolumn (ethyl acetate:hexane=1:4 v/v) to receive 4.00 g of FA-triepoxy(yield: 88%) with an epoxide equivalent weight 193 g/mol (theory: 187g/mol).

Fatty acids (100 g) and hydroquinone (0.25 g) are charged into a flask.The temperature is raised to 160° C., and acrylic acid (24.7 g) is addedslowly. The reaction is continued for 5 h at 160° C. after all theacrylic acid is added. The excess acrylic acid is first removed using arotary evaporator under vacuum, and then the crude product is distilledunder a 5 mmHg vacuum. The fraction between 210 to 240° C. is collected,receiving 103 g of yellowish liquid FA-diacid (yield: 97%).

The preparations of FA-diepxoy and FA-triepoxy follow a generalprocedure describe here. The synthesis of FA-diepoxy is similar to thatof FA-triepoxy. The product is purified using a silica gel column (ethylacetate:hexane=1:4 v/v), and the yield of pure FA-diepoxy is 85%. TheEEW of FA-diepoxy is 235 g/mol (theory: 231 g/mol).

Yet another embodiment is depicted in Scheme 8, which depicts silanemodified epoxy (dual curing, moisture curable). The DA is reacted withthe silane-modified epoxy to produce the DA-silane-epoxy.

The silicon epoxy compound 59 g, DA 50 g, toluene 75 g, trifluoroaceticacid 0.37 g are charged into a 250 mL flask equipped with a nitrogengas, thermometer and Dimroth condenser. The reaction is first conductedat 120° C. under stirring for 1 hour; subsequently, the temperature isgradually raised to 140° C. by distillation removing the generatedmethanol with toluene. The reaction is continued for 3 hours at 140° C.,and then the remaining toluene is distilled off under reduced pressure.A transparent liquid product of 88 g (yield 78%, DA-diepoxy-Silane) isobtained.

Thio Compound Curing Agents

In another embodiment, depicted in Scheme 9, fatty acid-derivedthio-compounds are utilized as curing agents (e.g., mercaptopropionicacid). The EHFA (such as a HFA reacted with m-CPBA above) undergoesmethanolysis prior to being reacted with 2-chloroethanol. Theintermediary is then reacted with mercaptopropionic acid to produce theFA-derived thio compound.

MEHFA is synthesized by oxirane ring opening reaction via refluxing EHFA(100 g) with excess methanol (136 g) in the presence oftetra-fluoroboric acid catalyst. The molar ratio of epoxy groups tomethanol is 1:11. The concentration of the catalyst is 1% of the totalweight of the EHFA and methanol. HFA, methanol and catalyst (amount ofeach reagent as described above) are added into a flask, then stirredand reflux for 1 h. After being cooled to room temperature, ammonia (30%in water) is added to neutralize the reaction mixture pH to 7. Thesolvent is removed on a rotary evaporator under a low vacuum at 60-95°C. The product of MEHFA is obtained with a yield of ˜98%.

Hydroquinone (3.0 g) and NaOH (8 g) are added to the mixture of 75.2 gMEHFA and 48.3 g 2-chloroethanol at room temperature and under stirring.After the mixture is refluxed for 4 h, it is cooled down to roomtemperature and filtered to remove the precipitate. The filtrate isadded to a large amount of water, and the product MEHFA-triol isprecipitated (yield ˜83%).

The mixture of MEHFA-triol (42.0 g), 3-Mercaptopropionic acid (40.0 g),and 1 wt % p-toluenesulfonic acid (p-TSA) solution (200 mL) in toluenein a 500 mL flask is refluxed for 4 h. After being cooled down, themixture is extracted by ethyl estate, and the organic layer is washed bywater. After the solvent is removed by rotatory evaporator, theresulting solid is dried by MgSO4 to give the product 5 (yield: 73-89%).

Another embodiment is depicted in Scheme 10, which depicts theutilization of sulfur (mercapto) functional silane. The intermediarydepicted in Scheme 9 is reacted with mercapto-functional silane insteadof mercaptopropionic acid to produce the FA-mercapto-functional silane.The reaction procedure is similar to that in Scheme 5.MEHFA-triol-silane is obtained with a yield of ˜79-85%.

Unless otherwise state above, tolerances for mass, volume, temperature,pH, molarity, and time is ±10.

TABLE 1 Flexural properties and T_(g)s of cured epoxies with differentDA-diepoxy/Rosin based diepoxy (DGEAPA) weight ratios DGEAPA/DA-diepoxyElastic (% DA-diepoxy in Flexural strength modulus Flexural T_(g)Samples epoxy mixture) (MPa) (GPa) strain % (° C.) a 5:0 (0) 108.5 ± 9.23.11 ± 0.15  3.7* ± 0.3 185 b 5:1 (16.7%) 119.5 ± 8.8 2.91 ± 0.07  4.5*± 0.3 163 c 5:3 (37.5%) 120.1 ± 6.1 2.63 ± 0.03 6.5** ± 0.8 132 d 5:5(50%) 106.6 ± 4.0 2.39 ± 0.05 6.6** ± 0.2 114 e 1:5 (83.3%)  50.7 ± 4.61.31 ± 0.08 5.6** ± 0.4 65 f 0:5 (100%)  4.4 ± 0.2 0.12 ± 0.02 8.0** ±1.0 43 *at break, **at yield. From K. Huang, J Zhang, M Li, J Xia, Y.Zhou, Industrial Crops and Products 2013, 49, 497-506.

As shown in Table 1, because of its long fatty chain, the curedDA-diepoxy resin alone exhibited a low glass transition temperature,T_(g) (43° C.), flexural strength (4.4 MPa) and modulus (0.12 GPa)(Table 1). In contrast, the cured rigid DGEAPA displayed high T_(g)(185° C.), flexural strength (108.5 MPa) and modulus (3.11 GPa).Addition of dimer acid-derived epoxy may flexibilize and toughen therosin-derived epoxy resin. From the application perspective, the mixedepoxies containing 20-40 wt % of DA-diepoxy exhibit overall highperformance. The results suggest that the rigid DGEAPA and the flexibleDA-diepoxy are complementary in many physical properties and the mixtureof the two in appropriate ratios may result in well-balanced properties.

Both FA-diepoxy and FA-triepoxy are liquid at room temperature and havelower viscosity than that of the commercial bisphenol A epoxy resinD.E.R.™ 332 (DER332). They also exhibited higher reactivity than DER332during curing. After curing with the same curing agent, nadic methylanhydride, the resulting resins exhibited T_(g)s as follows: DER332(168° C.)>FA-triepoxy (131° C.)>FA-diepoxy (80° C.)>epoxidized soybeanoil (ESO, 37° C.) as shown in Table 2. The difference in thermal andmechanical properties for the FA-derived resins is likely attributed tothe difference in their crosslink densities. That also explains why theT_(g) of the cured FA-diepoxy (80° C.) was lower than that of the curedFA-triepoxy (131° C.) but higher than that of ESO (37° C.). BecauseDER332 is a more rigid molecule than FA-triepoxy, it exhibited thehighest T_(g) among all the cure epoxies presented. Results from bendingtests indicate that the cured FA-triepoxy and DER332 had similarflexural strengths, but the latter had higher elastic modulus. Incontrast, the cured FA-diepoxy exhibited a lower flexural strength but acomparable modulus to that of the cured FA-triepoxy. TGA resultsindicate that the FA-derived epoxies exhibited thermal stability similarto that of DER332. The results also demonstrate that FA-diepoxy andFA-triepoxy are superior to ESO for epoxy applications.

TABLE 2 Flexural, impact properties and crosslink densities of NMA(nadic methyl anhydride) cured FA-diepoxy, FA-triepoxy and D.E.R. 332(Bisphenol A type epoxy) Flexural properties Impact strength Samplesstress (MPa) modulus (MPa) strain (%) (KJ/m²) T_(g (° C.)) FA-diepoxy 88.6 ± 2.1^(a) 2211.4 ± 56.4^(a) 8.1 ± 0.2^(a) 9.3 ± 1.3 80 FA-triepoxy121.4 ± 2.0^(b) 2621.3 ± 65.4^(b) 8.7 ± 0.2^(b)  79 ± 1.4 131 DER 332126.6 ± 30.1^(b) 3524.6 ± 124.6^(b) 6.3 ± 0.9^(b) 7.7 ± 1.2 168 ESO \ \\ \ 37 ^(a)at yielding point. ^(b)at breaking point. From K. Huang, P.Zhang, J. Zhang, S. Li, M. Li, J. Xia, Y. Zhou, Green Chemistry 2013,15, 2466-2475

Referring to FIG. 1, the monomer production process 100 charges a sodiumhydroxide solution in an ethanol-H₂0 mixture into a container (block102). The sodium hydroxide may be 16 g solution. The ethanol-H₂O may bea 140 mL solution (1:1, V/V). The container may be a 1-L three-neckedround-bottom flask equipped with reflux condenser, magnetic stirrer, andthermometer. The solution is heated to 70° C. (block 104). Hempseed oilis added dropwise added to the solution (block 106). 100 g of hempseedoil may be added utilizing a dropping funnel. The reaction is continuedat 70° C. for 2 hours (block 108). The reaction mixture is adjusted topH 2-3 (block 110). 1 M hydrochloric acid may be utilize to adjust thepH. The reaction is continued at 70° C. for another hour (block 112).The mixture is cooled (block 114). The mixture is extracted (block 116).Ethyl ether may be utilized as well as de-ionized (DI) water (e.g.,washed three times). The solution is dried (block 118). The ethyl ethersolution may be dried over magnesium sulfate. Vacuum distillation isperformed to remove the ethyl ether (block 120). The result is a viscousliquid hydrolyzed hempseed oil. The content of fatty acids inhydrolylzed hempseed oil may be estimated using Gas Chromatography-FlameIonization Detector (GC-FID) by a standard fatty acid methyl esters(FAME) procedure. The HFA is directly acrylated in the presence ofBF₃.Et₂O at 80° C. for 4 hours (block 122). The reaction conditions maybe the mixture of HFA, acrylic acid (AA) and BF₃.Et₂O in a molar ratiosof 1:27.4:1.37 under stirring. Depending on the size of reaction, twodifferent procedures may be employed. For the small size reactions, theexcess AA and catalyst are removed by NaHCO₃ aq. washing directly. Forthe large size reactions, the excess AA and catalyst are recovered bydistillation at 35-45° C. under reduced pressure, and the recovered AAand catalyst are reused. The yellow liquid acrylated hempseed fatty acid(AHFA) is obtained. The AHFA, benzyltrimethylammonium bromide (BTMAB),and hydroquinone is charged (block 124). A 100-mL round-bottom flaskequipped with a magnetic stirrer may be utilized into which to charge0.10 mol AHFA, 0.002 mol (2 mol % on fatty acid) of BTMAB, and 1 wt %hydroquinone. The mixture is warmed under argon atmosphere for about 15minutes in an oil bath preheated to 120° C. (block 126). Glycidylmethacrylate (GMA) is then added dropwise (block 128). 0.11 mol of GMAmaybe be added utilizing a dropping funnel. The reaction progress may bemonitored over 6 hours by thin layer chromatograph (TLC) using methylenechloride and ethyl acetate (7:3). Due to the competing side reactions,further addition of up to 0.1 molar equivalent of GMA and additionalreaction time may be utilized to react all of the AHFA. The reactionmixture is reacted for 8-10 hours (130 130). Two major oxiranering-opening products may be produced.

In some embodiments, a purified sample is produced. The dark-coloredreaction mixture may be cooled to room temperature and then passedthrough a short silica (200 mesh) column using 20% ethyl acetate inmethylene chloride to remove the catalyst and dark brown particulates. Ayellowish brown liquid is obtained.

Referring to FIG. 2, the monomer production process 200 chargesricinoleic acid, BTMAB, and hydroquinone (block 202). The ricinoleicacid, BTMAB, and hydroquinone may be charged into a 100-mL round-bottomflask equipped with a magnetic stirrer. 29.85 g (0.10 mol) ricinoleicacid (RA), 0.46 g (0.002 mol, 2 mol % on the basis of fatty acid) BTMAB,and 0.3 g (1 wt %) of hydroquinone may be utilized. The mixture iswarmed under argon atmosphere for 15 minutes in an oil bath preheated to120° C. (block 204). Glycidyl methacrylate (GMA) is added dropwise(block 206). 15.63 g (1.1 equivalent) of GMA may be added utilizing adropping funnel. The reaction progress may be monitored over 6 hours byTLC. Due to the competing side reactions, further addition of up to 0.1equivalent of GMA and additional reaction time may be utilized to ensureall of the RA reacted. The reaction proceeds for 8-10 hours (block 208).Two major oxirane ring-opening products are produced. To prepare thepurified sample for characterizations, the dark-colored reaction mixturemay be cooled to room temperature and passed through a short silica (200mesh) column using 20% ethyl acetate in methylene chloride to remove thecatalyst and dark brown particulates. A yellowish brown liquid (RA-GMA)is obtained. A catalytic amount of 4-(dimethylamino)pyridine (DMAP),triethylamine (TEA) (3 molar excess), and hydroquinone are added (block210). 0.12 g, 1 mol % of 4-(dimethylamino)pyridine (DMAP), 30.35 gtriethylamine (TEA) (3 molar excess), and 1 wt % hydroquinone may beadded. Methacrylic anhydride is added to the product mixture dropwise(block 212). 46.25 g, 0.3 mol; 3 equivalent to RA of methacrylicanhydride may be added to the product mixture. The reaction proceeds at70° C. for 4-6 hours under argon atmosphere (block 214). The reactionmay be monitored by TLC, which determined the presence of one majorproduct in addition to some minor impurities that account for unreactedexcess methacrylic anhydride, residual traces of GMA anddimethacrylates.

In some embodiments, the resultant is purified. The reddish brownreaction mixture is dissolved in ˜300 mL of methylene chloride andwashed with 500 mL (6×˜80 mL) each of distilled H₂O, 10% (v/v) dilutehydrochloric acid, saturated sodium bicarbonate (NaHCO₃) solution andsaturated brine. The organic phase is dried over anhydrous magnesiumsulfate (MgSO₄) and concentrated under reduced pressure at no more than60° C., yielding ˜40 g yellowish-dark brown liquid product (MARA-GMA).To prevent premature gelation, the product is stored in a closedcontainer, away from direct sunlight, UV, and heat sources.

Referring to FIG. 3, the monomer production process 300 epoxidizes thefatty acid. The fatty acid may be epoxidized by mixing 28 g of HFA and21.2 g of sodium carbonate in 20 mL methylene chloride (CH₂Cl₂). 73.6 gmeta-chloroperoxybenzoic acid (m-CPBA, 75 wt %) dissolved in CH₂Cl₂ at0.1 g/ml concentration may then be added dropwise at a reactiontemperature below 15° C., and then the reaction is reacted for 4 hoursto complete the epoxidation. The reaction mixture may be washed with 10wt % sodium sulfite and then by 10 wt % aqueous sodium bicarbonate.CH₂Cl₂ is removed by in vacuum rotary evaporation and 30 g productepoxidized hempseed oil fatty acid (EHFA, 96% yield) is obtained. Theproduct is then reacted with glycidyl methacrylate (block 304). First,31.2 g EHFA, 0.46 g, BTMAB and 0.3 g (1 wt %) of hydroquinone may bemixed in a flask. The mixture may be protected under argon atmosphereand placed in an oil bath of 120° C. for about 15 minutes. Glycidylmethacrylate (GMA, 15.63 g (1.1 equivalent)) is then added dropwise. Thereaction progress is monitored over 6 hours by TLC. The reaction mixturemay then be purified by silica gel column to remove the impurity byethyl acetate and methylene chloride, then product EHFA-GMA is obtained.EHFA-GMA is reacted with either acrylic acid/acrylic anhydride ormethacrylic acid methacrylic anhydride (block 306). 45.4 g EHFA-GMA,1.15 g BTMAB, and 0.9 g (2 wt %) of hydroquinone is mixed and allowed towarm under argon atmosphere for about 15 minutes in an oil bathpreheated to 100° C. The mixture of acrylic acid/acrylic anhydride (R═H)or methyl acrylic acid/methacrylic anhydride (R═CH₃)(acid/anhydride=0.15 mol/0.3 mol) is added dropwise into the reactionmixture. The reaction progress is monitored over 6 hours by TLC.Subsequently, the reaction mixture is purified by silica gel column toremove the impurity by ethyl acetate and methylene chloride.

Referring to FIG. 4, the monomer production process 400 receivesAHFA-GMA, RA-GMA, or EHFA-AA/MA-GMA (block 402). The received compoundis reacted with an acrylate silane group (block 404). The reactions maybe carried out in a flask equipped with a stirrer, dropping funnel,thermometer, and reflux condenser capped with a drying tube. The silaneagent may be mixed with AHFA-GMA, RA-GMA, or EHFA-AA/MA-GMA at a molarratio of 1:1 to 1:4 (based on the hydroxyl groups containing in thereagents), and the mixture may be stirred for 2-3 h at 90-100° C.Liberated methanol may be distilled off under reduced pressure (on arotary evaporator), giving the products of AHFA-GMA-A-Silane,RA-GMA-A-Silane, or EHFA-AA/MA-GMA-A-Silane. A methacrylate functionalgroup may also be utilized to produce AHFA-GMA-MA-Silane,RA-GMA-MA-Silane, or EHFA-AA/MA-GMA-MA-Silane when using methacrylatesilane as the silane agent.

Referring to FIG. 5, the monomer production process 500 receivesAHFA-GMA, RA-GMA, or EHFA-AA/MA-GMA (block 502). The compounds arereacted with vinyl functional silane (block 504). The reactions may becarried out in a flask equipped with a stirrer, dropping funnel,thermometer, and reflux condenser capped with a drying tube. The silaneagent may be mixed with AHFA-GMA, RA-GMA or EFA-AA/MA-GMA-H at a molarratio of 1:1 to 1:4 (based on the hydroxyl groups containing in thereagents), and the mixture may be stirred for 2-3 h at 90-100° C.Liberated methanol may be distilled off under reduced pressure (on arotary evaporator), to produce AHFA-GMA-V-Silane, RA-GMA-V-Silane, andEHFA-AA/MA-H-V-Silane.

Referring to FIG. 6, the monomer production process 600 determineswhether a dimer acid or a fatty acid is received (decision block 602).If a fatty acid is received, the fatty acid is reacted with eitheracrylic acid or fumaric acid to produce a fatty acid-derived diacid orfatty acid-derived triacid (block 604). To produce FA-triacid, 129 g ofcrude adduct of fumaric acid and conjugated FA may be dissolved in 500mL acetone and neutralized by 50% NaOH solution drop by drop until thepH value reaches 7. After the acetone is removed, the precipitatedtricarboxylic acid may then be extracted with ethyl acetate. The organiclayer may be neutralized using HCl and dried by NaSO₄ for 12 h and thenthe ethyl acetate may be removed using a vacuum rotary evaporator toobtain a white solid FA-triacid. To produce FA-diacid, fatty acids (100g) and hydroquinone (0.25 g) are charged into a flask. The temperatureis raised to 160° C., and acrylic acid (24.7 g) may be added slowly. Thereaction is continued for 5 h at 160° C. after all the acrylic acid isadded. The excess acrylic acid is first removed using a rotaryevaporator under vacuum, and then the crude product may be distilledunder a 5 mmHg vacuum. The fraction between 210 to 240° C. is collected,the yellowish liquid FA-diacid.

The dimer acid, fatty acid-derived diacid, or fatty acid-derived triacidare then reacted with epichlorohydrin to produce an epoxy (block 606).If a dimer acid, a 50 mL flask equipped with reflux condenser, magneticstirrer, and thermometer may be charged with 3.74 g DA, 18.5 gepichlorohydrin, and 0.023 g benzyltriethyl ammonium chloride. Thereaction temperature may then be raised to 117° C. and the reactioncontinued at that temperature for 2 h. The mixture may be cooled to 60°C., 0.8 g sodium hydroxide and 1.12 g calcium oxide is charged. Themixture may then be stirred at 60° C. for 3 h and then filtered bydiatomaceous earth (e.g., Celite®) and filter paper. The solid isdiscarded. After the excess epichlorohydrin is distilled under vacuum at100° C. from the filtrate, a light yellowish liquid product ofDA-diepoxy is obtained. If a FA-triacid, 3.5 g FA-triacid, 18.5 gepichlorohydrin and 0.061 g benzyltriethyl ammonium chloride are addedto a 50-mL flask are added. The reaction temperature is raised to 117°C. and the reaction continued for 2 h. After the mixture is cooled to60° C., 1.2 g sodium hydroxide and 1.68 g calcium oxide are charged. Themixture is stirred at 60° C. for 3 h and then filtered with powderCelite. After the excess epichlorohydrin is distilled under vacuum at100° C. from the filtrate, a yellowish viscous product (4.56 g) isobtained. The product is purified using a silica gel column (ethylacetate:hexane=1:4 v/v) to receive 4.00 g of FA-triepoxy with an epoxideequivalent weight 193 g/mol (theory: 187 g/mol). The synthesis ofFA-diepoxy may be similar to that of FA-triepoxy. The product may bepurified using a silica gel column (ethyl acetate:hexane=1:4 v/v), andthe yield of pure FA-diepoxy may be 85%. The EEW of FA-diepoxy is 235g/mol (theory: 231 g/mol). The monomer production process 600 then ends(done block 608).

Referring to FIG. 7, the monomer production process 700 receives a dimeracid (block 702). The dimer acid is then reacted with a silane-modifiedepoxy (block 704). Silicon epoxy compound 59 g, DA 50 g, toluene 75 g,and trifluoroacetic acid 0.37 g may be charged into a 250 mL flaskequipped with a nitrogen gas, thermometer and Dimroth condenser. Thereaction may first be conducted at 120° C. under stirring for 1 hour;subsequently, the temperature may be gradually raised to 140° C. bydistillation removing the generated methanol with toluene. The reactionis continued for 3 hours at 140° C., and then the remaining toluene isdistilled off under reduced pressure. A transparent liquid product ofDA-diepoxy-Silane is produced.

Referring to FIG. 8, the monomer production process 800 receives anepoxidized fatty acid (block 802). The epoxidized fatty acid thenundergoes methanolysis to produce MEHFA (block 804). MEHFA may besynthesized by oxirane ring opening reaction via refluxing EHFA (100 g)with excess methanol (136 g) in the presence of tetra-fluoroboric acidcatalyst. The molar ratio of epoxy groups to methanol may be 1:11. Theconcentration of the catalyst may be 1% of the total weight of the EHFAand methanol. HFA, methanol and catalyst (amount of each reagent asdescribed above) are added into a flask, then stirred and reflux for 1h. After cooled to room temperature, ammonia (30% in water) is added toneutralize the reaction mixture pH to 7. The solvent is removed on arotary evaporator under a low vacuum at 60-95° C. The MEHFA is thenreacted with 2-chloroethanol (block 806). Hydroquinone (3.0 g) and NaOH(8 g) may be added to the mixture of 75.2 g MEHFA and 48.3 g2-chloroethanol at room temperature and under stirring. After themixture is refluxed for 4 h, it may be cooled down to room temperatureand filtered to remove the precipitate. The filtrate is added to a largeamount of water, and the product MEHFA-triol is precipitated. TheMEHFA-triol is reacted with mercaptopropionic acid to produce theFA-derived thio compound (block 808). The mixture of MEHFA-triol (42.0g), 3-Mercaptopropionic acid (40.0 g), and 1 wt % p-toluenesulfonic acid(p-TSA) solution (200 mL) in toluene in a 500 mL flask may be refluxedfor 4 h. After cooled down, the mixture may be extracted by ethyl estateand the organic layer is washed by water. After the solvent is removedby rotatory evaporator, the resulting solid is dried by MgSO4 to givethe product.

Referring to FIG. 9, the monomer production process 900 receivesMEHFA-triol (block 902). The MEHFA-triol is reacted withmercapto-functional silane (block 904). The reaction procedure may besimilar to that depicted in the monomer production process 400.MEHFA-triol-silane is obtained.

What is claimed is:
 1. A compound having a structure of Formula III:

wherein: R¹ and R² are each independently

and R³ and R⁴ are each independently methyl or ethyl.
 2. The compound ofclaim 1, wherein the compound having the structure of Formula III hasone of the following structures:


3. A composition comprising the compound of claim 1 and a secondcompound.
 4. The composition of claim 3, wherein the second compound isa rosin-derived epoxy compound.
 5. The composition of claim 3, whereinthe composition includes the compound having the structure of FormulaIII at a concentration of 20% to 40% by weight.
 6. The composition ofclaim 3, wherein the compound having the structure of Formula III hasone of the following structures: